When angular velocity sensors, such as gyroscopic sensors or the like, are used, locations where the angular sensors are to be mounted and mount angles must be adjusted with high accuracy. However, during an actual mounting process, difficulty is encountered in ensuring accuracy for all of a plurality of mass-produced articles. There may arise a case where inclinations occur during mounting of the angular velocity sensors, whereby outputs from the angular velocity sensors differ from values which should be output originally. In a digital camera, the angular velocity sensors are used primarily for correcting camera shake and are materialized by a method for actuating an optical lens in accordance with an output from an angular velocity detection system including an angular velocity sensor, oscillating an image sensor, or the like. In order to correct camera shake with high accuracy, the motion of the camera acquired during camera shake must be accurately determined from an output from the angular velocity detection system.
Japanese Patent Laid-Open Publication No. Hei-5-14801 describes determining a differential motion vector in each field from an image signal output from a CCD; detecting an angular velocity of zero on the basis of the differential motion vector; and setting an offset voltage in accordance with a result of detection.
Japanese Patent Laid-Open Publication No. Hei-5-336313 describes determining a point spread function pertaining to an image signal output from a line sensor, and electrically correcting a positional displacement of the line sensor by means of the point spread function.
However, none of the above-described techniques are sufficient for calibrating the inclinations of the angular velocity sensors with high accuracy. In particular, when the angular velocity sensors are used for correcting camera shake, highly accurate calibration of an inclination is required. Moreover, since there is a potential of the image sensor also remaining inclined, calibration must be performed in consideration of the inclination of the image sensor. Further, even when the inclinations between the angular velocity sensors and the image sensor has been calibrated, there may arise a case where another error, such as a sensitivity error or a gain error, is included in the angular velocity detection system in a combined manner. Specifically, the angular velocity detection system is built of a sensor main body, a high-pass filter, a low-pass filter, and a detection circuit such as an amplifying circuit or the like; and includes, in a complex manner, an error in the sensitivity of the sensor main body, a gain error in an amplifying circuit, and the like. Meanwhile, when a point spread function is computed from outputs from the angular velocity sensors, the focal length of the lens of the camera is used as a calculation parameter. In addition to the errors in the angular velocity sensors, an error in the focal length of the lens can also pose a problem.